<template>
  <div class="sona">
    <h3>a传给b</h3>
    <button @click="btnClick">a传给b</button>
  </div>
</template>

<script>
export default {
  methods: {
    btnClick () {
      this.$bus.$emit('num', 1234567)
      console.log('num')
    }
  }
}
</script>

<style lang="scss" scoped>
.sona {
  width: 400px;
  height: 400px;
  background-color: pink;
}
</style>
